Breast-drill



e. E. CASSEL.

BREAST DRILL.

APPLICATION FILED FEB. 17, 1920.

Patented Aug. 16,1921.

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1 10 i y" r a w WA A I q r 5 G. E. CASSEL.

BREAST DR APPLICATION man r .1920.

1 ,387,92 1 Patented Aug. 16, 1921.

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STAT ES ATENT oFr eE. T

GU'NNAR ELIAS GASSEL, OF STOCKHOLM, SWED-EN,1ASSIGNOR T0 AKTIEBOLAGET GYRO', or. STOGKHOLM, swnnnrrn CORPORATION or SWEDEN.

' BREAST-DRILL.

. Specification of Letters Patent. Patented Aug. 16, 1921.

Application filed February' 17, 1920. serial ltl'o. 359,478.

To all whom it may concern: 7

Be i known that I, GUNNA ELIAs'CAs- SEL,9, citizen of the Kingdom of Sweden, residing at Stockholm, Sweden, have invented new and useful Improvements in Breast Drills, of which the following 'is a specification. 7'

This invention relates to abreast-drill in which a friction-ratchet gear is employed for the transmission of power "from the brace to the chuck. r In -my copending patent application Ser.

No. 359,479: I have described a friction; ratchet gear comprising annular elements mounted on a common shaft and having a. helicoidal friction surface between the driv};

The object of this invention is to enable. the use of such a friction ratchet gear in' connection with a breast-drill. One feature of the invention, therefore, consists in making the friction-ratchet gear reversible, so that a'uni-directed movement in the one direction or the other-may be imparted to. the

chuck by turning the brace back and forth.

More nearly stated, the said feature in-.

volves' that the driving and the locking ele-' ments of the friction ratchet gear are provided with-two. friction surfaces or two sets,

of friction surfaces one of said, surfaces or Y sets of surfacesoperating for the one direc tion of movement, while the other surface or set of surfaces operates for the other direction of movement.

Anotherfeature belonging to the above stated is the provision of means forbringbe clear from the following description; 5 In the accompanying drawings, a breasting the desired surfaces or sets of surfaces into operation.

Still other features of the invention will drill embodying this invention is illustrated. Figure 1 is a side-elevation of the breastdrill. Fig. 2 is a longitudinal section on a larger "scale throughQthe friction-ratchet gear and the chuck of thedrill. Fig. 3 is a longitudinal section through the casing" for the friction ratchet gear.

Fig. 4 is a plan view of saidcasing. F ig- 5 shown in plan view. Figs. 7, 8 and 9 are is a section on the line AA in Fig. 2. Fig. 6 is a section on the line .B-B in Fig. 2 with parts" of the friction-ratchet gear. Figs. '10, 11-

and 12'are corresponding views of the "lock-. ing element of the friction-ratchet gear;

Figs. l3and'1 l are elevation and end-views,. respectively, of an adjusting member of the,

friction-ratchet gear. Figs. 15and 16 are longitudinal section and cross-section on the line C-C in Fig. 15,.respectively, of same member. Fig. 17 shows the inner surface of the elements shown in Figs. 7-9 and 1012 in unfolded state and in engagement with one another.

The brace 1 of the breast-drill shown car ries in the known way the handles 2 and 3.

The lower end of the brace engages in a' sleeve 4: and is rigidly connected thereto by means of a locking pin 5. The sleeve 4 is formed integral with another-sleeve '6 havso inga larger diameter than that of the sleeve and forming right angles thereto, as isv v best shown in Fig. 3.

The sleeve 6 carries a'chuck' and a friction: ratchet gear for the transmission of power from the brace 1 to said chuck. The sleeve 6 is'close'd at its lower end by a'bottom plate 7 provided with a central opening through which extends .a spindle 8. The spindle 8 rests on the said bottom with an enlarged] portion. comprising a lower cylindrical part 9 andan. upper conical part 10.' Extending upwardly. from the cone 10 is a stem or spindle 11 the diameterofwhich is less than that of the spindle 8.

The cone 10 supports an annularmember 12 having aconical recess in its lower end surrounding the lower portion of the stem 11." The part of the member 12 surrounding the stem 11 has a reduced outer diameter in which the cone fits, the member. 12 also I of said member 12 so as to form a s oulderjj 13. The upper reduced portion of the mem- 3 ber 12 isformed with outwardly extending,

projections 14: at diametrically opposite j points. The upper end surface of the mem-' ber 12 is cam-shaped and consists of helicoidal surfaces 15 and 16 inclined alternatingly in opposite directions, as shown in Fig. 17.

Resting on the shoulder 13 of the ring 12 is a ring 17 rotatably mounted in the sleeve 6. Said ring 17 is shown in details in Figs. 13-16. The ring 17 is formed in its lower surface with two diametrically opposed openings 18. In said openings the projections 14 of the ring 12 are adapted to engage, as shown in Fig. 5. In the sides of the openings 18 there are formed borings 19 (Fig. 16) adapted to receive springs 20', 20 bearing against the sides of the projections 14 (Fig. 5). For limiting the rotation of the ring 17 relatively to the sleeve 6, the

7 ring 17 is formed with a recess 21 (Fig. 16)

on its outer side to be engaged by a stop screw 22 inserted in the sleeve 6 (Figs. 2 and 5). w I

.Insertedin the upper endof the sleeve 6 is acover or plug23 provided with a downwardly extending cylindrical projection 24. The plug 23 isshown in details in Figs. 79. The projection 24 depends into the space between the ring17 and the stem 11 and is formed on its lower edge with a cam surface corresponding to the cam surface 15, 1.6 of the ring 12 and consisting of helicoidal surfaces 25,26, inclined alternatingly in opposite directions said surfaces being adapted to cotiperate with the helicoidal surfaces 15,

i 16. The helicoidal surfaces 15, 16, 25, 26

are so arranged as to permit a certain relative rotation of the members 12, 24, so that only the surfaces 15 and 25 or the surfaces 16 and 26 maybe in contact with each other at the same time. p

Mounted in the sleeve 4 is a bolt 27 which is both rotatable and axiallymovable. Said bolt 27 extends into the sleeve 6 and carries at its inner end a cam 28 made integral with the bolt. Loosely engaging the said end of the bolt 27 is a screw 29 carrying a diametrically arranged wedge 30 outside the end of the bolt. The cam 28 engages a lateral opening 31 (Figs. 13-16) in the ring 17, and the. wedge 30 extends through a lateral opening 32 (Figs. 78) formed in the member 24. The stem 11 is formed with arecess 33 (Fig. 6) to be engaged by the I wedge 30.

Secured in a transverse hole in the bolt 27 is a screw pin 34 extending through a slot 35 formed in the sleeve 4, said. pin being attached with its outer end to a serrated ring v36 rotatably and slidably mounted on the sleeve 4. The slot 35 extends around the upper half of. the periphery of the sleeve 4, as

shown in Figs. 3 and 4. Midway between the endsof the slot 35 an. axial recess 37 is formed in the wall of the slot nearest to the sleeve 6, similar recesses 38, 39 of a smaller axial extension being formed at the ends of the slot 35. Situated between the ends of the brace 1 and the bolt 27 in the sleeve 4 is a pressure spring 40, tending to move the bolt 27 toward the stem 11.

The spindle8 extending through the bot- 'tom'7 of thesleeve-6 carries a chuck below formed at its lower end with a conical mouth 44, surrounding the conical jaws 45 mounted in the sleeve 43 and engaging the lower end of the spindle 8. By screwing the sleeve 43 upwardly or downwardly the jaws 45 may be moved together or apart.

The operation-pf the breast-drill is' as follows: Assuming the parts are in the position shown in Fig. 2, a rigid connection exists between the brace 1 and the stem 11 so that the stem and thus thegspindle 8 with the chuck will be moved with the brace, whether thebrace is rotated in the one direction or theother. .In said position the pin 34.engages the central lateral recess 37 of the slot 35 the wedge 30 being, therefore, in engagement with the slot 33in the stem 11. Now the parts 12 and 17 are in the relative position shown in Fig. 5 in which the projections 14 are. centered in the open ngs 18, and the springs 20, 2O counterbalance each other. I v

If it is desired to rotate the chuck in the direction indicated by the arrow a in Fig. 1 by turning the brace backand forth, the operator grasps the ring 36 and moves the same to the right (Fig. 2) thereby removing the pin 34 from itsengagement in the recess 37 whereupon the ring 36 is turned in clockwise direction, till the pin 34 snaps into the recess 38. movement of the ring 36, the wedge 30 was brought out of engagement with the recess 3 3 in the stem 1 1,and said engagement will not be restored when the pin 34"snaps into the recess 38, as said recess is too shallow to allow such engagement. During the turning of the ring "36 with the bolt 27 the wedge 30 is maintained in its position in register with the recess 33 due to its engagement in the opening 32 in the member 24. This is possible on account of the loose engagement of the screw 29 in the bolt 27.

In the longitudinal Upon the turning of the bolt 27 the can: i

shown in Fig. 2 into the position shown in Fig. 6. In said movement the cam 28 acts on the ring 17 and turns same in clockwise direction from a central position, in which the opening 31 is in axial register with the bolt 27, into the position shown in Fig. 6. This movement of the ring 17 causes the springs 20 to turn the ring 12 in the direction indicated by the arrow 7) in Fig. 17 into a position relative to the member 24, in which the inclined surfaces 15 are in contact with the inclined surfaces25, as shown in Fig. 17, the springs being then further compressed and tend to stillmove the ring 12 in the same direction, but as the member 24 is stationary, said action of the springs will cause. the member 12 to slide on the surfaces 15 so as tobe pressed.

the casing 4, 6 and the member 24 with it.;

Said movement of the member 24 is indicated. by the arrow a in Fig. 17. The in-.

clined surfaces 25 are thus caused to exert a downwardly directed pressure on the member 12. Due to this'pressure the member 12 will be pressed against the cone 10 so as to interlock the members 24, 12 and 10. As a good contact was secured at thecontact surfaces by the action of the springs 20' previous to the operation of the brace 1, the said interlocking will take place without any back-lash at the same instant that the brace is operated.

In returning the brace, the pressure from the member 24 on the member 12 will cease immediately thereby releasing the interlocking of the parts and permitting the compressedsprings 20 to immediately take with it the ring 12, which will in this movement slide on the cone 10. The returning of the brace will thus be effected without the need of any power for releasing the interlocking of the parts of the friction ratchet gear. In other words, the friction ratchet gear operates without any back-lash in the forward movement and completely without any shock in the reverse movement.

If it is desired to turn the chuck 'tin the opposite direction to that indicated by the arrow a in Fig. 1 by oscillating the brace 1, the ring 12 is moved in counter-clockwise direction, until the pin 34 snaps into the lateral recess 39. This will result in a re lease of the springs 20 and a compression of the springs 20 which will then move the ring 12 to effect contact between the inclined surfaces 1.6 and 26.

For attaining the above said purpose, viz., no back-lash in the forward movement and no shock in the reverse movement, the friction ratchet gear is SO constructed as to answer to the following conditions: The clutch member 12 is made self-releasing with respec to the helicoidal friction surfaces, inasmuch as the angle of inclination of said surfaces is greater than twice the angle of friction of same surfaces. Furthermore, the clutch member 12 is made self-releasing with respect to the conical friction surface inasmuch as the top angle of the conical surface is greater'than twice the angle, of friction ofsaid surface. Said two conditions will secure the self releasing action of the friction ratchet gearuponreverse movement of the driving. element of'said; gear. In order that the device maybe self-locking in the forward movement of the drivingelement, that is whenthe clutch element 12is sub-' jected to pressure from the member 24, it is necessary that the angle of inclination of the helicoidal or inclined surfaces is less than the sum of the angle of. friction of said surfaces and the ideal angle of friction of the cone. 'A more detailed explanation of said conditions is given .in my copend-. ing patent application erial No. 359,479.

1 Having now described my invention, what I claim as new. is

1. In a breast-drill, thecombination of a brace, a chuck, a casing rigidly connected with said brace, and a reversible friction ratchet gear in said casing for imparting a "unidirected movement to the chuck upon an oscillating movement of the said brace.

2. In a breast-drill, the combination of a brace, a sleeve-shaped casing rigidly con' nected to said brace, a spindle mounted in said casing and carrying a chuck outside thereof, a cone on said spindle, a ring loosely mounted on said cone and having-inclined friction surfaces on its upper end, another ring rigidly connected to the said casing and having inclined surfaces on its lower-side for engaging with the said first-mentioned in clined surfaces.

3. In a breast-drill, the combination of a brace, a casing rigidly connected to said brace, a chuck carried by said casing, a reversible frictionratchet gear mounted in said casing for imparting a unidirected movement to the chuck upon an oscillating movement of the brace, and means for reversing said friction ratchet gear.

4. In a breast-drill, the combination of a brace, a casing rigidly connected to said brace, a spindle mounted in said casing and carrying a chuck outside thereof, a cone on said spindle, a ring loosely mounted on said cone and having in its upper end one set of inclined friction surfaces for each dir'ece tion of movement, another ring rigidly connected to said casing and having correspond.- ing sets of inclined friction surfaces for engagement with said first mentioned surfaces, and means for operating the said first-mentioned ring to bring it into contact with the one set of inclined surfaces or the other on the said other ring.

5. In a breast-drill, the combination of a brace, a casing rigidly connected to said brace, a spindle mounted in said casing and carrying a chuck, a cone on said spindle, a ring loosely mounted on said cone and having two sets of inclined friction surfaces, another ring rigidly connected to the said casing and having corresponding sets of inclined friction surfaces, springs acting on said firstmentioned ring, and means for causing the springs to move the said ring into engagement with one set of inclined surfaces or the other of said other ring.

6. In a breast-drill, the combination of a brace, a casing rigidly connected to said brace, a chuck carried by said casing, a reversible friction ratchet gear in said casing for imparting a unidirected movement to the chuck upon oscillation of the brace,springs for reversing said gear, a ring loosely mounted in said casing for the operation of said springs, and a manually controlled cam for operating said ring. I

7. In a breast-drill, the combination of a brace, an angularly shaped sleeve rigidly connected to said brace, a spindle mounted in said sleeve and carrying a chuck outside thereof, a reversible friction ratchet ear between said spindle and said sleeve, springs for reversing said gear, a ring mounted concentrically to said spindle for operating said springs, a manually controlled cam rotatably and longitudinally movable at right angles to said spindle for operating the said ring, and a projection on said cam for directly engaging in said spindle, When the cam is out of operation.

In testimony whereof I have signed my name;

GUNNAR ELIAS OASSEL. 

